Secondary lens assemblies which can be removably attached to the front of conventional eyewear, are popularly used to convert conventional eyewear to sunglasses. Among various designs magnets have been used for attaching secondary lens assemblies to conventional eyewear. For example, a conventional eyewear frame may include a magnetic material secured around the peripheral portion, facilitating attachment of a second lens assembly to the conventional eyewear frame, such as described in U.S. Pat. No. 4,070,103 of Meeker, or the magnets may be secured to the temporal portions of a conventional frame that mate with similar magnets in a secondary lens assembly, such as described in U.S. Pat. No. 5,416,537 of Sadler. Those magnets are embedded in portions of the eyewear frames in a vertical orientation for mating with similarly positioned magnets in the secondary lens assembly. These secondary lens assemblies are therefore held in place in front of the conventional eyewear frame only by the magnetic forces and are not supported to prevent the secondary lens assemblies from moving vertically relative to the conventional eyewear frames, which may allow unexpected detachment of the secondary lens assemblies from the conventional eyewear frames. Efforts have been made and continue to be made to address this problem.
There is a need to develop an improved design for eyewear with attachable secondary lens assemblies to overcome the shortcomings of the conventional designs thereof.